Fort Rotterdam is a 17th-century fort in Makassar on the island of Sulawesi in Indonesia. It is a Dutch fort built on top of an existing fort of the Gowa Kingdom. The original fort, Jum Pandan (allegedly named after the pandanus trees growing in the vicinity), gave its name to the city Ujung Pandang, another name for the city of Makassar.

Fort Rotterdam was built on the location of an earlier Makassarese fort, called Ujung Pandang. Although it has been claimed by some authors that this fort dates back to 1545, there is no direct evidence for this, and it seems more likely that the fort was built in 1634, as part of a fortification programme that the Makassar rulers undertook in response to a war with the Dutch East India Company which broke out in this year.

In 1667 Fort Ujung Pandang was ceded to the Dutch as part of the Bungaya Treaty, after the defeat of Gowa in the Makassar War. It was in subsequent years entirely rebuilt on the initiative of Dutch admiral Cornelis Speelman to become the center of Dutch colonial power in Sulawesi. It was renamed Fort Rotterdam after Speelman’s place of birth. In the years 1673-1679 it got its five bastions and the ‘turtle’ shape it still has to this day. This shape gave the fort the nickname “Benteng Penyu” (“sea-turtle fort”). The stone for the construction of the fort was taken from the karst mountains in Maros, the limestone from Selayar and the woods from Tanete and Bantaeng. Following the Java War (1825–1830), Javanese prince, and now national hero, Diponegoro was imprisoned in the fort following his exile to Makassar in 1830 until his death in 1855. It was also used as a Japanese prisoner of war camp in World War II.

Fort Rotterdam remained the regional Dutch military and governmental headquarters until 1930s.[3] After 1937, the fort was no longer used as a defense. During the brief Japanese occupation it was used for conducting scientific research in the field of linguistics and agriculture, after which it fell into disrepair. In the 1970s, the fort was extensively restored.